Magnetic resonance flow measurements in real time: Comparison with a standard gradient‐echo technique

Ultrafast gradient systems and hybrid imaging sequences offer the opportunity to acquire phase contrast flow data in real time. In a 1.5‐Tesla magnetic resonance (MR)‐tomograph, peak velocity and volume flow were assessed in 36 large vessels (aorta) and 33 medium‐sized vessels (carotid and iliac artery) using a real‐time (segmented k‐space turbo gradient‐echo planar imaging sequence) in comparison with a gradient‐echo technique. With the real‐time technique, the matrix was reduced from 116 to 64, and temporal resolution changed from 30 msec to 124 msec. Measurements of peak velocity correlated in large (r = 0.88) and medium‐sized vessels (r = 0.81). Volume flow measurements correlated in large vessels (r = 0.87), however, a poor correlation (r = 0.64) was found in medium‐sized vessels. Thus, scan time can be significantly reduced and images acquired without electrocardiogram (ECG)‐triggering. Flow volume can only be determined in large vessels with sufficient accuracy, mainly due to reduced spatial resolution in smaller vessels.J. Magn. Reson. Imaging 2001;14:306–310. © 2001 Wiley‐Liss, Inc.